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dmaengine: Convert ID allocation to an IDA 

dmaengine currently uses an IDR to allocate DMA IDs, but it only needs
to know whether IDs are in use or not; the ID to pointer functionality
of the IDR is unused.  That means it can use the more space-efficient IDA.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Matthew Wilcox 2016-12-15 08:57:51 -08:00 committed by Vinod Koul
parent 0c744ea4f7
commit adc064cd9f
1 changed files with 11 additions and 10 deletions
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21
drivers/dma/dmaengine.c
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@ -65,7 +65,7 @@
#include <linux/mempool.h> #include <linux/mempool.h>
static DEFINE_MUTEX(dma_list_mutex); static DEFINE_MUTEX(dma_list_mutex);
static DEFINE_IDR(dma_idr); static DEFINE_IDA(dma_ida);
static LIST_HEAD(dma_device_list); static LIST_HEAD(dma_device_list);
static long dmaengine_ref_count; static long dmaengine_ref_count;
@ -162,7 +162,7 @@ static void chan_dev_release(struct device *dev)
chan_dev = container_of(dev, typeof(*chan_dev), device); chan_dev = container_of(dev, typeof(*chan_dev), device);
if (atomic_dec_and_test(chan_dev->idr_ref)) { if (atomic_dec_and_test(chan_dev->idr_ref)) {
mutex_lock(&dma_list_mutex); mutex_lock(&dma_list_mutex);
idr_remove(&dma_idr, chan_dev->dev_id); ida_remove(&dma_ida, chan_dev->dev_id);
mutex_unlock(&dma_list_mutex); mutex_unlock(&dma_list_mutex);
kfree(chan_dev->idr_ref); kfree(chan_dev->idr_ref);
} }
@ -898,14 +898,15 @@ static int get_dma_id(struct dma_device *device)
{ {
int rc; int rc;
mutex_lock(&dma_list_mutex); do {
if (!ida_pre_get(&dma_ida, GFP_KERNEL))
return -ENOMEM;
mutex_lock(&dma_list_mutex);
rc = ida_get_new(&dma_ida, &device->dev_id);
mutex_unlock(&dma_list_mutex);
} while (rc == -EAGAIN);
rc = idr_alloc(&dma_idr, NULL, 0, 0, GFP_KERNEL); return rc;
if (rc >= 0)
device->dev_id = rc;
mutex_unlock(&dma_list_mutex);
return rc < 0 ? rc : 0;
} }
/** /**
@ -1035,7 +1036,7 @@ err_out:
/* if we never registered a channel just release the idr */ /* if we never registered a channel just release the idr */
if (atomic_read(idr_ref) == 0) { if (atomic_read(idr_ref) == 0) {
mutex_lock(&dma_list_mutex); mutex_lock(&dma_list_mutex);
idr_remove(&dma_idr, device->dev_id); ida_remove(&dma_ida, device->dev_id);
mutex_unlock(&dma_list_mutex); mutex_unlock(&dma_list_mutex);
kfree(idr_ref); kfree(idr_ref);
return rc; return rc;